The loudspeaker module is an important acoustic component in portable electronic devices. As an energy conversion device, it is used to complete the conversion between an electrical signal and an acoustic signal. A conventional loudspeaker module generally comprises a housing accommodating a loudspeaker unit, and the loudspeaker unit divides the whole inner cavity of the module into a front vocal cavity and a rear vocal cavity. In order to reduce the F0 (low frequency) of the module and widen the band width, a sound absorption element is often provided in the rear vocal cavity. In recent years, it is found that, by filling the rear vocal cavity with a porous material and taking advantage of the property of the porous material to rapidly adsorb/desorb gas in the rear vocal cavity, the resonance space can be virtually enlarged, thereby the resonant frequency F0 of the module is reduced more effectively. Before being filled into the rear vocal cavity, the porous material is generally required to be filled into a plastic hauling shell first, then be packaged by silk screen cloth, be manufactured into a sound absorption component and finally be fixed in the rear vocal cavity of the module. In such a method, the porous material is packaged to be the sound absorption element first and then filled into the rear vocal cavity, so the process is simple and easy and the packaging effect is good. However, the plastic hauling shell does not have sound absorption effect, and has no contribution in reducing the module F0; on the contrary, it occupies the space of the rear vocal cavity. In the present, as loudspeaker devices are increasingly miniaturized, it is quite practical and significant to more effectively utilize the space of rear voice cavities.
Additionally, before the porous material is packaged to form the sound absorption component, it is required to add an adhesive agent into the raw powder to conduct granulation to prevent micro powders from leaking and diffusing into the loudspeaker unit and affecting the acoustic performance of the module. However, micro powders will be generated during the collision between the sound absorbing particles and the hauling shell. In order to prevent that micro powders are generated during the collision between the sound absorbing particles and the hauling shell, the amount of the adhesive agent added should be increased to ensure the strength of the particles, but if too much of the adhesive agent is added the pore paths of the porous material will be blocked, and the gas adsorption and desorption ability of the material will decrease, thereby the sound absorption performance of the sound absorbing particles will deteriorate, and the sound absorption effect cannot meet the requirements of the expected acoustic performance of the products. In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.